Ayzlee McCarthy, of Elk Horn, spent December 26 running around the house with her siblings and playing with her Christmas gifts: dress-up clothes and a doll of the snowman OlafAyzlee from the Disney movie ‘Frozen.’

A day later, her legs ached so badly, she couldn’t walk.

Then on December 28, Ayzlee was rushed to a hospital in Des Moines and hooked up to an IV.

She died the following morning, just 13 days after her third birthday, of influenza A and B with sepsis, The Des Moines Register reported.

Her distraught mother, Amber McCarthy, is struggling to understand.

She was healthy, she had a flu shot — the whole thing is so unreal,’ Amber McCarthy told the Des Moines Register.